Many communities operate emergency 911 call answering systems, also called "E911 call answering systems" or public safety answering position (PSAP) equipment. These systems are typically computer-controlled telephone switching systems that receive 911 calls at a central emergency services dispatching center and connect the calls to emergency services dispatchers via the E911 trunk lines. The E911 calls are routed to the dispatching center by telephone company central offices, and are answered by dispatchers who determine the caller's physical location by computer assistance, ascertain the type and severity of the caller's needs, and dispatch appropriate emergency services.
The computer system is typically used to receive automatic number identification ("ANI," also known as "caller ID" information) from the telephone call, use the caller ID to index a computer database to determine the calling party's location (address), and display the calling party's location on a graphical display. These computer-assisted operations facilitate the assignment of an appropriate emergency service vehicle and personnel.
Many of these E911 call-answering systems operate under control of a multi-threaded multi-tasking operating system (MTOS). However, these MTOSs have a known propensity to fail or "lock up" under unknown conditions. If the failure occurs during the handling of an emergency call, the dispatcher can lose communication with the distressed calling party, who may be in a life-threatening situation. It goes without saying that such a failure is extremely undesirable. Although the computer-based emergency 911 system can usually be rebooted, valuable time has been lost. Even if the situation is not life threatening and the calling party calls back, the failure of the system is disruptive.
Accordingly, there is a need for a system to detect the possible failure of a computer-operated E911 call answering system. There is a further need in the art for a system that can keep emergency 911 calls from being dropped during a failure of the underlying computer system of the emergency 911 call answering system.